A material was fabricated based on the Schiff base reaction to achieve covalent attachment of NH₂-MIL-53(Al) and the 3-formylsalicylic acid ligand (3-FSA) for fluorimetric detection of Zn²⁺ ions based on inhibition and destruction of CN isomerization and ESIPT. The low limit of detection and limit of quantification were calculated at optimum conditions. The selectivity of the 3-FSA sensor was achieved against some interfering ions. The new sensor was applied for the determination of Zn²⁺ ions in cosmetic cream products and the obtained results were validated through comparison with ICP-OES. The data indicated that the 3-FSA sensor provided a sensitive, selective, fast, direct and efficient determination of Zn²⁺ ions with good reproducibility and reversibility.